Desiccant cartridges containing desiccant particles are common in automotive air conditioning systems for dehydrating refrigerants. These desiccant cartridges are adapted to fit within canisters of receiver/dryer (R/D) and accumulator assemblies.
Although various forms of R/D and accumulator assemblies have been suggested in the prior art, the types used in automotive air conditioning systems generally include an elongated canister having inlet and outlet ports communicating with the interior thereof. The outlet port may consist of a fluid flow tube used to return the air or fluid flowing from the entry end of the canister to the exit end. A desiccant cartridge holding desiccant particles is positioned in the interior of the canister allowing for air or fluid to move through the desiccant particles.
Desiccant containing cartridges such as those shown in U.S. Pat. Nos. 5,814,136; 5,716,432; 5,685,087; 5,569,316; 5,540,348; 5,529,203; and 5,522,204 are disposed in the R/D and accumulator assemblies and function to dry the liquid refrigerant as it passes from the assembly inlet through to an outlet port contained in the structure.
Some dryer canisters are welded shut after the desiccant cartridge is inserted. Notably, the heat created from the welding process can be problematic in that it may result in detrimental dimensional changes to the desiccant cartridge resulting in an improper seal between the cartridge and canister. It is important that the desiccant cartridge conform to the dimensions of the canister in order to form a secure fit within the canister and to form a proper seal between the cartridge and the canister. An improper seal can cause leakage within the receiver/dryer or accumulator assembly, or into the environment. Internal leakage can create icing within the air conditioning system, and environmental leakage can create a loss in fluid pressure as well as create potential health and environmental risks. As such, an improper seal can reduce the effectiveness of the air conditioning system.
To keep a desiccant cartridge secure within a receiver dryer or accumulator assembly and form a proper seal, desiccant cartridges have employed various retention or sealing devices. One type of sealing device used on today's desiccant cartridges includes a continuous flange, or seal, made of polypropylene plastic. The seal is provided on the outer wall of the desiccant cartridge and is intended to provide a seal between the cartridge and the canister. However, the polypropylene is somewhat rigid such that the seal can be damaged when the desiccant cartridge is installed in a canister thereby creating an improper seal. Also, the polypropylene has a tendency to curl and harden from heat during welding shut of the canister resulting in detrimental dimensional changes to the seal.
Notably, the desiccant cartridge of the present invention includes a seal of high heat resistance and excellent flexibility thereby avoiding detrimental dimensional changes to the seal and improper sealing between the cartridge and the canister. This seal preferably is a thermoplastic elastomer, most preferably SANTOPRENE®.